1.2. Cell ultrastructure

1.2. Ultrastructure of cells

Miltiadis-Spyridon Kitsos Platon IB Diploma

http://www.pathologyoutlines.com/images/salivary/01_21.jpg




The official IB Diploma Biology guide

The resolution of the electron microscopeElectron microscopes have a much higher resolution than light microscopes.

Resolution is defined as the shortest distance between two points on a specimen that can still be distinguished by the observer or camera system as separate entities.

Thus, as the resolution of an imaging system increases the quality and the detail of the image increases as well.

http://www.lab.anhb.uwa.edu.au/hb313/main_pages/timetable/lectures/Image6.gif

https://youtu.be/VWxYsZPtTsIhttp://www.nanoscience.com/files/cache/1cb19595ba7acd226ff2c9d5acea6c10_f280.jpg






https://youtu.be/VWxYsZPtTsI




http://www.nanoscience.com/files/cache/1cb19595ba7acd226ff2c9d5acea6c10_f280.jpg





The resolution of the electron microscopeElectron microscopes have a much higher resolution than light microscopesFacts• Light wavelengths are in the range of 400-700 nm which limit the

resolution of the the light microscope. • The maximum magnification of an optical microscope is X1000. • A beam of electrons has a wavelength of 2.5 to 12.2 pm, which

permits a higher resolution in the SEM in relation to the light microscope

• The maximum resolution of an electron microscope is 1 nmResolution

mm μm nm

Human eye 0.1 100 100,000

Light microscope 2 X 10-4 0.2 200

Electron microscope

1 Χ 10-6 0.001

1

The ancestors: ProkaryotesProkaryotes have a simple cell structure without compartmentalization

Haemophilus influenzae bacteria attaching to a surface as seen by a scanning electron microscope. Image: Paul Webster, PhD http://www.hearingreview.com/2014/07/scientist-finds-link-antibiotics-bacterial-biofilm-formation-cause-chronic-ear-sinus-lung-infections/

http://www.hearingreview.com/2014/07/scientist-finds-link-antibiotics-bacterial-biofilm-formation-cause-chronic-ear-sinus-lung-infections/



The ancestors: ProkaryotesProkaryotes have a simple cell structure without compartmentalizationProkaryotes= pro + karyon (Greek, nucleus); those without nucleus

https://youtu.be/U-Gyae41L5s

https://youtu.be/KrTwHXbsFcM










The ancestors: ProkaryotesDrawing of the ultrastructure of prokaryotic cells based on electron micrographs

Cell wall

Plasma membraneNucleoid

70s ribosomes

cytoplasm

70s ribosomes

cytoplasm

Cell wall

Plasma membrane

Nucleoid

Pilli

You don’t draw things that you don’t see in the micrographs.

The purpose of this practical is to identify structures by drawing them

http://image.slidesharecdn.com/ibbiology1-150428204627-conversion-gate02/95/ib-biology-12-slides-ultrastructure-of-cells-7-638.jpg?cb=1430655519







Cell division in prokaryotesApplication: Prokaryotes divide by binary fission.

https://d2jmvrsizmvf4x.cloudfront.net/WLR0dWIhSZeBuAJSHwYs_11-02_BinaryFission_0_L.jpg

http://cronodon.com/images/Bacteria_dividing_3b.jpg

http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::500::500::/sites/dl/free/0073375225/594358/BinaryFission.swf::BinaryFission




















ProkaryotesMedia

http://www.sheppardsoftware.com/health/anatomy/cell/bacteria_cell_tutorial.htm http://www.wiley.com/college/boyer

/0470003790/animations/cell_structure/cell_structure.htm

http://www.cellsalive.com/cells/bactcell_js.htm https://www.blackwellpublishing.com/trun/artwork/Animations/Overview/overview.html

http://www.sheppardsoftware.com/health/anatomy/cell/bacteria_cell_tutorial.htm




http://www.wiley.com/college/boyer/0470003790/animations/cell_structure/cell_structure.htm








http://www.cellsalive.com/cells/bactcell_js.htm




https://www.blackwellpublishing.com/trun/artwork/Animations/Overview/overview.html









Cell division in prokaryotesApplication: Prokaryotes divide by binary fission.























The eukaryotesEukaryotes appeared circa 2.5 billion years ago. Their appearance coincides with the enrichment of the atmosphere with oxygenThe increased availability of oxygen allowed the evolution of more metabolic pathways which yielded more energy to be invested in size and more complex structures

http://www.nature.com/nature/journal/v455/n7216/full/nature07381.html

Read more

http://evolution.berkeley.edu/evolibrary/images/news/grypaniagraph.gif











The Eukaryotes: being compartmentalizedEukaryotes have a compartmentalized cell structure

Compartmentalized: divided into compartments (sur-rounded by a single or double membrane)

Advantages of compartmentalization

• Enzymes and substrates for a particular process are more concentrated.

• Lytic enzymes can be isolated inside a membranous organelle

• Create optimum conditions for a particular process.

• Organelles with their contents can move around in the cell.

Comp1 Comp2

Comp3 Comp4

http://blog.canacad.ac.jp/bio/BiologyIBHL1/files/1197811.jpg

Comp1

Comp2

http://www.cellsalive.com/cells/cell_model_js.htm








The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs.

This is a typical annotated sketch of a liver cell. o The sketch is missing a scale baro Can you spot any other

problems?

Now compare this sketch with an actual TEM photo of a liver cell.

Deduce whether the sketch represents accurately the photo

http://www.tokresource.org/tok_classes/biobiobio/biomenu/eukaryotic_cells/liver_cell_500.jpg

http://images.fineartamerica.com/images-medium-large/tem-of-liver-cell-science-source.jpg
















The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs.

Lysosomes

Nuclear membrane/Nuclear pores

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmic reticulum

80s ribosomes Mitochondria

Nucleolus


Do the same with this sketch

Plasma membrane





The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs

Eukaryotes have a compartmentalized cell structure

http://images.fineartamerica.com/images-medium-large-5/nucleus-tem-david-m-phillips.jpg

https://scbiologi.files.wordpress.com/2014/08/nucleus2.jpg?w=444

Nucleus

• Double membrane with pores• Contains the DNA associated with proteins (chromatin)• During interphase, uncoiled chromatin is found

throughout the nucleus• Densely stained areas of chromatin around the edge of

the nucleus • DNA replication• RNA transcription – RNA exits through the pores

http://highered.mheducation.com/sites/0073031216/student_view0/exercise3/anatomy_of_the_nucleus.html















http://www1.udel.edu/biology/Wags/histopage/empage/ecu/ecu16.gif

Rough/ Smooth Endoplasmic reticulum

• Consist of flattened membrane sacs - cisternae• Rough endoplasmic has 80s ribosomes attached• Synthesis of proteins for secretion• Following translation, proteins enter the cisternae and

are carried by vesicles towards the Golgi apparatus. • Smooth associated with the metabolism of fats and

steroid hormones• no ribosomes attached

http://highered.mheducation.com/sites/0073031216/student_view0/exercise3/animal_cell.html

http://3219a2.medialib.glogster.com/media/ba/ba809f577d71c8037c41fc1b18ebd07bbb3f4198dbf287dd59c4fb98b38316d8/smooth-and-rough-er.jpg




















The Golgi Apparatus

• Like ER, consists of flattened membrane sacs - cisternae

• Presence of a large number of vesicles • Processes proteins arriving from the rER. • Most of the proteins will be carried to the membrane

for secretion https://upload.wikimedia.org/wikipedia/commons/a/a9/Human_leukocyte,_showing_golgi_-_TEM.jpg

https://micro.magnet.fsu.edu/cells/golgi/images/golgifigure1.jpg

https://upload.wikimedia.org/wikipedia/commons/a/a9/Human_leukocyte,_showing_golgi_-_TEM.jpg















Lysosomes

• Spherical organelles, single membrane• Formed from Golgi vesicles• High concentrations of proteins (digestive) enzymes -

densely stained in electron micrographs. • Enzymes are used in breaking down food particles in

vesicles. http://jennarever.weebly.com/uploads/1/3/6/0/13609849/183821_orig.jpg?225

https://micro.magnet.fsu.edu/cells/lysosomes/images/lysosomesfigure1.jpghttp://highered.mheducation.com

/sites/0072495855/student_view0/chapter2/animation__lysosomes.html

http://jennarever.weebly.com/uploads/1/3/6/0/13609849/183821_orig.jpg?225



https://micro.magnet.fsu.edu/cells/lysosomes/images/lysosomesfigure1.jpg



http://highered.mheducation.com/sites/0072495855/student_view0/chapter2/animation__lysosomes.html








Vacuoles and vesicles

• Organelles with a simple membrane and fluid inside.• Large vacuoles are characteristic features of plant cells.• Food particles in vacuoles (food vacuoles) are digested

with the aid of enzymes found in lysosomes • Unicellular organisms use vacuoles (contractile

vacuoles) to expel excess of water.• Vesicles are very small vacuoles to transport materials

inside the cell.

http://www.doctorc.net/Labs/Lab3/IMAGES/ORG16.JPG

http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/vacuole.jpg

http://learn.genetics.utah.edu/content/cells/vesicles/

• See fluorescent-stained vacuoles travelling in the cytoplasm of a eukaryotic cell.
















Mitochondrion• Spherical or ovoid shape• Double (Inner and outer) membrane• Inner invaginated membranes - cristae. • Inner semi-viscous fluid - matrix • Sites of ATP production during aerobic cell respiration.• Structure and function revisited in Topic 8 (AHL)

http://atropos.as.arizona.edu/aiz/teaching/a204/images/mitochondria.gif

https://upload.wikimedia.org/wikipedia/commons/0/0c/Mitochondria,_mammalian_lung_-_TEM.jpg

Think: Why these mitochondria differ in shape?

https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Animal_mitochondrion_diagram_en_(edit).svg/2000px-Animal_mitochondrion_diagram_en_(edit).svg.png

https://youtu.be/RrS2uROUjK4































Free (80s) ribosomes • Non membranous structures • Same as ribosomes attached to the rER• 20 nm in diameter• Inner semi-viscous fluid - matrix • Constructed in nucleolus from rRNA and proteins• Structure and function revisited in Topics 3 and 7 (AHL)

http://iws.collin.edu/biopage/faculty/mcculloch/1406/notes/cell/images/ribosome.jpg

https://upload.wikimedia.org/wikipedia/commons/f/f9/The_Biological_bulletin_%2819755382264%29.jpg

https://ka-perseus-images.s3.amazonaws.com/d3027730681b4cda353ea0e3895b6670ce9024ea.png









https://upload.wikimedia.org/wikipedia/commons/f/f9/The_Biological_bulletin_(19755382264).jpg










Chloroplasts (plant cells only)• Spherical or ovoid shape• Double (Inner and outer) membrane• Stacks of flattened sacs - thylakoids• Inner semi-viscous fluid - stroma• Site of photosynthesis – production of glucose which is

then packed in starch granules. • Structure and function revisited in Topic 8 (AHL)

http://66.media.tumblr.com/tumblr_lurw6vSOYR1r4zla1o1_400.jpg

http://4206e9.medialib.glogster.com/media/be854f6410ca1e5a792c30c0c1782c67b4f5626ff2a1a52d2905627fd760e27a/chloroplast-grana-en.jpg

https://adapaproject.org/images/biobook_images/A000169_chloroplast_struc.jpg

https://youtu.be/cFVsvgiQdx8


















Centriole (animal cells only)• 9 x triplets of cylindrical protein fibres• Organization of the mitotic spindle – anchor point for

microtubules• Microtubules also support cilia and flagella.

http://cache1.asset-cache.net/gc/128558784-transmission-electron-micrograph-of-a-gettyimages.jpg?v=1&c=IWSAsset&k=2&d=6U2k5nAuQXuSn8AU2xzaoMCXF2acj3GMmlsrmYgJJwxKerKK3tW3%2FGeOiTg0hp6K

https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Centriole-en.svg/320px-Centriole-en.svg.png

https://vimeo.com/58347006http://www.discovery.org/multimedia/video/2010/02/centriole-animation/

http://cache1.asset-cache.net/gc/128558784-transmission-electron-micrograph-of-a-gettyimages.jpg?v=1&c=IWSAsset&k=2&d=6U2k5nAuQXuSn8AU2xzaoMCXF2acj3GMmlsrmYgJJwxKerKK3tW3/GeOiTg0hp6K














https://vimeo.com/58347006



http://www.discovery.org/multimedia/video/2010/02/centriole-animation/







Flagellum (animal cells only)• Central bundle of microtubules - axoneme• 9 outer doublet microtubules -one singlet centre• Locomotion

Cillia (animal cells only)• Also used in locomotion• Numerous projections from the plasma membrane• Microtubules

https://upload.wikimedia.org/wikipedia/commons/6/68/Chlamydomanas_reinhardtii_Flagella_5_-_TEM.jpg

Watch: Euglena locomotion-flagellumWatch: Ciliated protozoa

http://remf.dartmouth.edu/images/ciliaTEM/image/lung_cilia_80299-100.jpg

https://youtu.be/jl0TzaWUQWk https://youtu.be/TTbS7_vZLNg








https://youtu.be/jl0TzaWUQWk



https://youtu.be/TTbS7_vZLNg







Cell wall (plant cells only)

• Cell wall is not an organelle but an extracellular component.

• Made of cellulose (polysaccharide) Gives the cell a definite shape and structure. Provides structural support to the cell. helps in osmotic-regulation. Prevents water loss. It prevents the cell from rupturing due to tugor

pressure.

Watch: Plant cell plasmolysis

http://www.doctortee.com/dsu/tiftickjian/cse-img/botany/plant-anat/cell/plant-cell-tem.jpg

https://amit1b.files.wordpress.com/2009/12/cell-wall-diagram.jpg

https://youtu.be/gWkcFU-hHUk






















Microvilli (singular microvillus)

• Finger-shaped plasma membrane protrusions• Increase the cell surface area.• Facing lumen where exchange occurs (e.g., intestinal

mucosa)

Watch: short video on microvilli


http://i3.cpcache.com/product/1119289765/intestinal_microvilli_tem_tile_coaster.jpg?height=460&width=460&qv=90

http://study.com/cimages/multimages/16/microvilli.PNG


















TasksIdentify as many organelles as you can. Deduce the function of the cell

The Eukaryotes: being compartmentalizedSkill: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.

Slide concept by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html

http://www.bioknowledgy.info/12-ultrastructure-of-cells.html



Nu. = nucleusMit. = abundant mitochondria – cell with a high energy demandrER = very well developed rough endoplasmic reticulumVes. = many secretory vesiclesAnimal cell (no cell wall) specialized in secretingPancreatic secretory cell


Slide concept by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html

NU.

rER

Ves.

Mit.




TasksIdentify as many organelles as you can. Deduce the function of the cell



NU.

Chl.Va.

CW

Nu. = nucleus, on the side of the cell Va. = Vacuole, large vacuole in the centerChl.= chloroplasts, with thylakoids and lamellasCW=Cell wallPlant cell from palisade mesophyll

1.2.S3 Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.

What organelles can you identify? Think about the role of the organelles that occur most common and deduce the function of the cell.

http://www.vcbio.science.ru.nl/images/tem-plant-cell.jpgSlides by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html

http://www.vcbio.science.ru.nl/images/tem-plant-cell.jpg







1.2.S3 Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.

What organelles can you identify? Think about the role of the organelles that occur most common and deduce the function of the cell.


Evidence & conclusions:• Cell wall present – must be a plant cell• No chloroplasts – must be found inside the stem or in the roots• Vacuoles relatively small – the cell does not have a storage,

transport or support function• Nucleus relatively large / cell size small – likely to be a new cell

recently undergone mitosis• Possibly recently divided cell tissue from a plant root

Is in fact: a plant cell found at the root-tip

Slides by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html








EukaryotesMedia


http://www.tvdsb.ca/webpages/brownt12/files/index1.htm

http://learn.genetics.utah.edu/content/cells/insideacell/ http://www.sumanasinc.com/webcontent/animations/content/eukaryoticcells.html












http://learn.genetics.utah.edu/content/cells/insideacell/





http://www.sumanasinc.com/webcontent/animations/content/eukaryoticcells.html






http://www.stepsinbiology.eu/

1.2. Cell ultrastructure

Education

Transcript of 1.2. Cell ultrastructure